1. Field of the Invention
Embodiments of the invention relate to a device and a method for working with electromagnetic fields, specifically those fields that occur in image-guided nuclear spin tomography devices. (“MRT” or “MRI” stand for magnetic resonance tomography and magnetic resonance imaging respectively, wherein these two acronyms are used interchangeably herein).
2. Description of the Related Art
Although MRI examinations are becoming increasingly important in diagnostic medicine, some patients are contraindicated for MRI exams. Such a contraindication can be the result of an at least partially implanted medical device (hereinafter also implant or IMD). In addition to the MRI examinations, other technical applications also present a danger for the users of medical devices or implantable medical devices, particularly when these generate strong electromagnetic interference fields (EMI, Electro Magnetic Interference) in the surrounding area.
To make MRI examinations possible in spite of that, various approaches are known that relate either to conducting the MRI examination or to the implantable medical device.
Among others, technologies for the recognition of magnetic fields are known that are based on conventional methods for detecting magnetic fields. Thus, US 2008/0154342 describes a process using a GMR sensor (Giant Magnetic Resistance) for recognizing problematic magnetic fields of MRT devices. This technological methods are, however, not very specific and generate an increased requirement of energy, which leads to a shorter service life for the same energy reserves.
Also known in prior art is publication US 2005/0070787, which describes a setup that coordinates switching off certain components of an implanted medical device that are switched off during the delivery of electromagnetic irradiation impulses. To do so, a communication from the MRI device to the implant is required in which the information of the chronological progression from the MRI device to the implant are transmitted. Up to now, such a communication between implant and MRI devices is not provided so that an application is possible only after an upgrading of MRI devices and implants or at least of the MRI devices. Further, prior art does not make any additional solutions available that replace the components that are switched off, by means of which an adapted operating mode of an implanted medical device and/or a continual monitoring process of the physiological parameters of an implant carrier is not ensured in each case. Additionally, prior art is dependent because of the necessary communication between implant and MRI device, as a consequence of which other sources of interference are not recognized and cannot be taken into consideration during operation.